Learn the Basque Plural (AK, OK, EK)

Today we're going to speak about the plural.
It's known we create plurals in Basque with AK.
For instance, zale (which means fan, keen on sth), its plural is ZALEAK.
But what's the difference between ZALEAK, ZALEEK and ZALEOK? Are the three of them plurals?
Let's analyse it by using some examples.
euskarasatorra...